Flue gas may include any number of contaminant species including particulate matter, acids, and/or various oxides, including, for example, SO2, SO3, HCl, and nitrous oxides. Contaminant impurities may be detrimental to the environment, and it may be required to remove contaminant impurities to at least a statutory level of regulation. A number of processes have been designed to facilitate removal of contaminants and purification of flue gas. However, there remains a need for flue gas processing systems that more efficiently remove contaminant gases. Particularly, there is a need for cost effective strategies of flue gas processing that may be applied and/or retrofit in existing structures with certain restrictions.